Showing posts with label Exercise. Show all posts
Showing posts with label Exercise. Show all posts

Acting Our Age?


One prerequisite for a good nights sleep for adults is some healthy exercise during the day. At least that seems to be in the direction where most of the evidence is pointing. We like to make sure our children are well exercised too and we often express the sentiment after a hectic day out that “they’ll certainly sleep well tonight.”

But will they? A study by Pesonen et al on 275 8-year olds puts this old wisdom in doubt (1). They strapped accelerometers onto the wrists of their young subjects to measure activity and followed the group for a week to measure their sleep patterns.

Shock horror! Contrary to legend and their own hypothesis, lots of exercise did not improve the sleep patterns. The duration and quantity of sleep were both reduced in response to moderate or vigorous activity compared to more couch-potato days.

Why would that be they wondered, as do we all? They suggest that the body response of their youngsters to high physical activity is to increase their cortisol levels and this stress hormone could be keeping them on high alert. Surprisingly, the problem with vigorous activity was not related to the time of day, so even if it was avoided in the evening, the sleep patterns were still disrupted.

This difference between young and adult experience, perhaps, points to a different way that vigorous activity is felt. As we get older, maybe we don’t get so excited and just plow on trying to get through it and back to our armchairs, whilst our youngsters are fully mentally engaged, so their excitation level is high. Does this mean that we oldies have forgotten how to enjoy life like the youngsters?

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022958

Keep Limping Along


We all wish to stay healthy, but once in a while we catch something nasty. Severe bacterial infections can be very nasty and, with the increasing problem of antibiotic resistance build; we have to be careful as to permanent damage to our system, especially as we get older.

Now if we take a deep breath and leave humans and turn to lab rats we can study the longer-term damage of a severe bacterial infection without any likelihood of subsequent lawsuits. The current information is that healthy, but elderly rats, after they catch something nasty in the bacterial line and then get cured, show rather severe memory impairment. Younger rats don’t. The brain inflammation in the older critters that severe bacterial infections can cause is also severe and lasts a long time.

The long-term effects are that the ability to make new connections (plasticity) is much reduced and that a type of nerve growth factor (brain-derived neurotrophic factor, BDNF) has had its production severely curtailed. Now BDNF works in those crucial areas for memory and learning new and important stuff like finding your way through a maze, namely the hippocampus and the cortex. The hippocampus generates some neural stem cells so that we can continue to replace some neurons.

All is not lost for our furry friends. Barrientos et al from the U of Colorado have just published a solution, which will undoubtedly work for us too (1). They have found that regular exercise after the bout of nasty bacteria, increases the BDNF in the hippocampus and lo and behold those elderly rats that took daily voluntary exercise got back to their amazing maze solving, whilst their sedentary friends did not.

Of course, being elderly, the rats were skipping about rather gently and couldn’t manage more that half a mile a week. But that was sufficient. Even better though was the result that regularly exercising elderly rats didn’t have the severe neuro-inflammatory effect from a bacterial infection. So once again, we have the strong message to get out there and exercise. It may be good for the heart, but it’s even better for the brain!

  1. R.M. Barrientos, M.G.Frank, N.Y.Crysdale, T.R.Chapman, J.TAhrendsen, H.E.W.Dasy, S.Gampeau, L.R.Watkins, S.L Patterson & S.F.Maier, J. Neuro. Sci., 31, 11578, (2011)